var events=require('events');

var eventEmitter=new events.EventEmitter();

var connectHandler=function connected(){
    console.log('连接成功.');
    eventEmitter.emit('data_received');
}

eventEmitter.on('connection',connectHandler);

eventEmitter.on('data_received',function(){
   console.log('数据接收成功.');
});


eventEmitter.emit('connection');
console.log("程序执行完毕.");